Training

There are quite a few scripts/tools out there that will help
in automatically generating a toolchain, a root filesystem,
a ROM image, and other components of an embedded Linux system.

This is a collection of such tools, scripts, tipps and tricks:

buildroot: http://www.uclibc.org/cgi-bin/cvsweb/buildroot/
This is a set of scripts maintained by Erik Andersen (uClibc,
BusyBox?, TinyLogin?, etc.) that can be used to build quite a
few components (including toolchain for host and target
binaries.) Though I haven't used buildroot, the content of
the scripts is one of the best I've seen (well organized
and thorough).

Craig Hollabaugh's build scripts: http://www.embeddedlinuxinterfacing.com/sourcecode.shtml
These are the scripts Craig used in his "Embedded Linux"
book. There is a buildtoolchain.tar.gz, which is the set
of script used to build the toolchain, and there's
buildrootfilesystem, which is used to ... well, build
the root filesystem